Air brake electric control valve

ABSTRACT

An air brake electric control valve includes a valve body, a force balance unit including a guide member, and an electromagnetic urge unit including a movable column operable to move between an urging position and a retracted position. When the movable column is at the urging position, the movable column pushes the air guide member such that a through hole of the air guide member is blocked. When the movable column is at the retracted position, a gap is formed between the movable column and the air guide member such that an intermediate section and a second passage of the valve body are in fluid communication via the through hole of the air guide member and the gap.

FIELD

The disclosure relates to a brake, and more particularly to an air brakeelectric control valve.

BACKGROUND

A conventional air brake system includes a plurality of brake calipersor drum brakes that are manually operated to perform the brake function.Generally, the conventional air brake system can be divided into aservice brake subsystem and a parking brake sub-system.

The service brake sub-system is adapted to be operated to decelerate orstop a moving vehicle. For example, in rear-axle brake of theconventional air brake system, the service brake sub-system is operatedvia a pedal, which controls a pressure-release mechanism. Referring toFIG. 1 , when the pedal is depressed, air is supplied into a brakechamber 91 of a brake cylinder 9 of the brake calipers or the drumbrakes, so that the brake cylinder 9 performs a brake function.High-pressure air is decompressed by the pressure-release mechanism, soas to be conditioned to have an appropriate pressure before entering thebrake chamber 91 of a brake cylinder 9. When the pedal is depressedgreatly, the decompression effect of the pressure-release mechanism isinferior, and the air having relatively high pressure is introduced intothe brake chamber 91 to generate an intense brake function. When thepedal is not depressed, the effect of the pressure-release mechanism issuperior, and no air is introduced into the brake chamber 91 so that thebrake cylinder 9 does not perform the brake function.

The parking brake sub-system is for keeping a vehicle stationary.Generally, the parking brake sub-system is controlled by amanually-operated valve. The manually-operated valve may be a three-porttwo-position valve. Referring to FIG. 2 , when the manually-operatedvalve is at a first position, air is supplied into a parking brakechamber 92 of the brake cylinder 9 so that the brake cylinder 9 does notperform the brake function. When the manually-operated valve is at asecond position, air ceases to be supplied into the parking brakechamber 92 of the brake cylinder 9 so that the brake cylinder 9 performsthe brake function.

It should be noted that when air is introduced into both the brakechamber 91 and the parking brake chamber 92 of the brake cylinder 9 orwhen no air is introduced into the brake chamber 91 and the parkingbrake chamber 92 of the brake cylinder 9, the brake cylinder 9 performsthe brake function. Specifically, when the vehicle is traveling, air iscontinuously introduced into the parking brake chamber 92. Air isintroduced into the brake chamber 91 to generate the brake function whenthe vehicle desires to decelerate or stop. When the vehicle is parking,no air is introduced into the brake chamber 91 and the parking brakechamber 92 of the brake cylinder 9, and the brake cylinder 9 performsthe brake function.

However, manual operation may not be reliable. When the vehicle parkstemporarily without depression of the pedal and without switching themanually-operated valve to the second position, the vehicle may not bekept stationary. An electric control technique may alleviate such adrawback.

Referring to FIG. 3 , a conventional electric control technique forcontrolling the brake cylinder 9 includes steps of: detecting a pressurein a relay valve 83 that is output from an electromagnetic valve 82 by apressure sensor 81; feeding the value of the pressure to an electroniccontrol unit (ECU) 84 so that the ECU 84 is able to determine how tocontrol the electromagnetic valve 82; and outputting the pressure in therelay valve 83 to the brake cylinder 9. The abovementioned componentsare costly and are controlled in a complex way. Moreover, it takes along period of time and a considerable budget to substitute amanually-controlled brake system with an electrically-controlled brakesystem.

SUMMARY

Therefore, an object of the disclosure is to provide an air brakeelectric control valve that can alleviate at least one of the drawbacksof the prior art.

According to the disclosure, the air brake electric control valveincludes a valve body, a shuttle member, a force balance unit and anelectromagnetic urge unit. The valve body has a first passage, a secondpassage that transversely intersects the first passage, a third passagethat transversely intersects the first passage, and a fourth passagethat transversely intersects the first passage. The first passage has anend that forms a first inlet. The second passage has an end thatcommunicates with the other end of the first passage opposite to thefirst inlet, and an opposite end that forms a vent hole. The thirdpassage is disposed adjacent to the first inlet, and has an end thatcommunicates with the first passage, and an opposite end that forms anoutlet. The fourth passage is disposed adjacent to the second passage,and has an end that communicates with the first passage, and an oppositeend that forms a second inlet. The first passage further has anintermediate section that is located between the third passage and thefourth passage. The shuttle member is disposed at an intersectionbetween the first passage and the third passage. The force balance unitincludes an air guide member that extends from the intersection betweenthe first passage and the second passage toward the intersection betweenthe first passage and the fourth passage, and an air guide spring thatsurrounds the air guide member. The air guide member further has athrough hole that extends in the extending direction of the firstpassage. The air guide member is operable to move between a first airguide position and a second air guide position. The air guide springresiliently biases the air guide member toward the second air guideposition. The electromagnetic urge unit is disposed at the other end ofthe first passage opposite to the first inlet. The electromagnetic urgeunit has a coil, a movable column that is driven by the coil, and anelectromagnetic spring that abuts against the movable column. Themovable column is operable to move between an urging position and aretracted position. The electromagnetic spring resiliently biases themovable column toward the retracted position. When the movable column isat the urging position, the movable column is moved against the biasingaction of the electromagnetic spring to project out of the coil, andpushes the air guide member with an urge force such that the throughhole of the air guide member is blocked and that the air guide member ismoved to the first air guide position against the biasing action of theair guide spring. When the movable column is at the retracted position,the movable column is biased by the electromagnetic spring to retractinto the coil, and a gap is formed between the movable column and theair guide member such that the intermediate section is in fluidcommunication with the second passage via the through hole of the airguide member and the gap, and that the air guide member is biased tomove to the second air guide position by the air guide spring.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the disclosure will become apparent inthe following detailed description of the embodiment with reference tothe accompanying drawings, of which:

FIG. 1 is a sectional view illustrating a conventional brake cylinderperforming brake function;

FIG. 2 is sectional view illustrating a conventional brake cylinder notperforming the brake function;

FIG. 3 is block diagram illustrating a conventional electric controltechnique;

FIG. 4 is a schematic view illustrating an electric control air brakesystem;

FIG. 5 is a perspective view illustrating an air brake electric controlvalve according to the disclosure;

FIG. 6 is a sectional view taken along line VI-VI in FIG. 5 ,illustrating a shuttle member at a first blocking position;

FIG. 7 is a view similar to FIG. 6 , illustrating the air brake electriccontrol valve at an initial state;

FIG. 8 is a view similar to FIG. 6 , illustrating the air brake electriccontrol valve at a pressure-increasing state;

FIG. 9 is a view similar to FIG. 6 , illustrating the air brake electriccontrol valve at a pressure-maintaining state;

FIG. 10 is a view similar to FIG. 6 , illustrating the air brakeelectric control valve at a pressure-release state;

FIG. 11 is an assembled perspective view illustrating two of the airbrake electric control valves being integrated;

FIG. 12 is a perspective view illustrating the air brake electriccontrol valve being connected to a relay valve;

FIG. 13 is a perspective view of an air parking brake electric controlvalve;

FIG. 14 is a sectional view taken along line XIV-XIV in FIG. 13 ,illustrating a valve core at a first action position;

FIG. 15 is a view similar to FIG. 14 , illustrating the valve core at asecond action position;

FIG. 16 is a sectional view taken along line XVI-XVI in FIG. 13 ,illustrating the air parking brake electric control valve at a releasestate;

FIG. 17 is a view similar to FIG. 16 , illustrating the air parkingbrake electric control valve at a first phase state;

FIG. 18 is a view similar to FIG. 16 , illustrating the air parkingbrake electric control valve at a second phase state;

FIG. 19 is a view similar to FIG. 16 , illustrating the air parkingbrake electric control valve at a lock state; and

FIG. 20 is a perspective view of the air parking brake electric controlvalve, illustrating the configuration of an intake passage and a ventpassage.

DETAILED DESCRIPTION

Before the disclosure is described in greater detail, it should be notedthat where considered appropriate, reference numerals or terminalportions of reference numerals have been repeated among the figures toindicate corresponding or analogous elements, which may optionally havesimilar characteristics.

Referring to FIG. 4 , an electric control air brake system 1 includes anair supply unit 100, a manual control pressure regulator 110, anelectric control pressure regulator 120, two front axle brake cylinders130, a first electric control unit 140, an air parking brake manualvalve 150, an air parking brake electric control valve 160, two rearaxle brake cylinders 170, a second electric control unit 180, a frontaxle relay valve 191, a rear axle relay valve 192, a parking brake relayvalve 193, and four anti-lock electromagnetic valves 194.

The air supply unit 100 supplies air with a first pressure (P1). Thefirst pressure (P1) is higher than an ambient air pressure. The airsupply unit 100 includes a front axle reservoir 101, a rear axlereservoir 102 and a parking brake reservoir 103. Specifically, the airsupply unit 100 employs an air compressor to compress the ambient air tothe first pressure (P1), and distributes the air with the first pressure(P1) to the front axle reservoir 101, the rear axle reservoir 102 andthe parking brake reservoir 103. The front axle reservoir 101, the rearaxle reservoir 102 and the parking brake reservoir 103 are fortemporarily storing, the compressed air, and the air pressure in thefront axle reservoir 101, the rear axle reservoir 102 and the parkingbrake reservoir 103 is also the first pressure (P1).

It should be noted that in FIG. 4 , a plurality of the front axlereservoir 101, and a plurality of the rear axle reservoir 102 are shownfor illustrating how the compressed air is distributed. However, onlyone front axle reservoir 101 and only one rear axle reservoir 102 areable to distribute the compressed air to the locations shown in FIG. 4 .

The manual control pressure regulator 110 has a first inlet 111 that isconnected to the front axle reservoir 101, a first outlet 112 thatcorresponds to the first inlet 111, a second inlet 113 that is connectedto the rear axle reservoir 102, and a second outlet 114 that correspondsto the second inlet 113. The air inputted via the first inlet 111 ismanually controlled to be conditioned to a second pressure (P2), and isoutputted via the first outlet 112. The air inputted via the secondinlet 113 is manually controlled to be conditioned to a third pressure(P3), and is outputted via the second outlet 114. The manual controlpressure regulator 110 is well-understood in the art, and will not befurther described in the following paragraphs.

The electric control pressure regulator 120 includes a front axle airbrake electric control valve 121 and a rear axle air brake electriccontrol valve 121′. The front axle air brake electric control valve 121has a first inlet 122 that is connected to the first outlet 112 of themanual control pressure regulator 110, a second inlet 123 that isconnected to the front axle reservoir 101, an outlet 124 and a vent hole125. The air inputted via the second inlet 123 of the front axle airbrake electric control valve 121 is electrically controlled to beconditioned to a fourth pressure (P4). The air output from the outlet124 of the front axle air brake electric control valve 121 has a fifthpressure (P5). The fifth pressure (P5) is equal to a greater one of thesecond pressure (P2) and the fourth pressure (P4). The rear axle airbrake electric control valve 121′ has a first inlet 122′ that isconnected to the second outlet 114 of the manual control pressureregulator 110, a second inlet 123′ that is connected to the rear axlereservoir 102, an outlet 124′ and a vent hole 125′. The air inputted viathe second inlet 123′ Of the rear axle air brake electric control valve121′ is electrically controlled to be conditioned to a sixth pressure(26). The air outputted from the outlet 124′ of the rear axle air brakeelectric control valve 121′ has a seventh pressure (P7). The seventhpressure (P7) is equal to a greater one of the third pressure (P3) andthe sixth pressure (P6).

The front axle air brake electric control valve 121 and the rear axleair brake electric control valve 121′ of the electric control air brakesystem 1 are structurally identical to each other, are the same type ofair brake electric control valve 2, and are different from each other inthe connection among other components. The air brake electric controlvalve 2 would be described in detail in the following paragraphs.

The front axle brake cylinders 130 are driven by the fifth pressure(P5), and perform a brake function when the fifth pressure (P5) ishigher than the ambient air pressure. The first electric control unit140 generates a first electric signal (S1) for controlling the frontaxle air brake electric control valve 121, and a second electric signal(S2) for controlling the rear axle air brake electric control valve121′. The front axle brake cylinders 130 of the electric control airbrake system 1 are well-understood in the art, and will not be furtherdescribed in the following paragraphs.

The air parking brake manual valve 150 is configured as a normally-openthree-port two-position valve, and is manually operable to be switchedbetween a traveling position and a parking position. The air parkingbrake manual valve 150 has an inlet 151 that is connected to the parkingbrake reservoir 103, an outlet 152 and a vent hole 153. When the airparking brake manual valve 150 is in the traveling position, the inlet151 and the outlet 152 of the air parking brake manual valve 150 are influid communication, and the vent hole 153 and the outlet 152 of the airparking brake manual valve 150 are not in fluid communication. When theair parking brake manual valve 150 is in the parking position, the inlet151 and the outlet 152 of the air parking brake manual valve 150 are notin fluid communication, and the vent hole 153 and the outlet 152 of theair parking brake manual valve 150 are in fluid communication. The airparking brake manual valve 150 of the electric control air brake system1 is well-understood in the art, and will not be further described inthe following paragraphs.

The air parking brake electric control valve 160 includes an air valveunit 161, and a self-lock unit 162 that is mounted to the air valve unit161. The air valve unit 161 configured as a normally-open three-porttwo-position valve, and is electrically operable to be switched betweena first position and a second position. The air valve unit 161 has aninlet 163 that is connected to the outlet 152 of the air parking brakemanual valve 150, an outlet 164, and a vent hole 165. When the air valveunit 161 is in the first position, the inlet 163 and the outlet 164 ofthe air valve unit 161 are in fluid communication, and the vent hole 165and the outlet 164 of the air valve unit 161 are not in fluidcommunication. When the air valve unit 161 is in the second position,the inlet 163 and the outlet 164 of the air valve unit 161 are not influid communication, and the vent hole 165 and the outlet 164 of the airvalve unit 161 are in fluid communication. The self-lock unit 162 iselectrically operable to be switched between a release position and alock position. When the self-lock unit 162 is in the release position,the air valve unit 161 is switchable between the first position and thesecond position. When the self-lock unit 162 is in the lock position,the air valve unit 161 is locked at the second position. The air parkingbrake electric control valve 160 will be described in detail in thefollowing paragraphs.

Each of the rear axle brake cylinders 170 has a first inlet 171 forreceiving the seventh pressure (P7), and a second inlet 172 forreceiving the compressed air from the outlet 164 of the air parkingbrake electric control valve 160. Each of the rear axle brake cylinders170 performs a brake function when the seventh pressure (P7) isapproximate to the ambient air pressure and when the pressure in thesecond inlet 172 thereof is approximate to the ambient air pressure.Each of the rear axle brake cylinders 170 performs the brake functionwhen the seventh pressure (P7) is higher than the ambient air pressureand when the pressure in the second inlet 172 thereof is approximate tothe ambient air pressure. Each of the rear axle brake cylinders 170 doesnot perform the brake function when the seventh pressure (P7) isapproximate to the ambient air pressure and when the pressure in thesecond inlet 172 thereof is higher than the ambient air pressure. Therear axle brake cylinders 170 of the electric control air brake system 1are well-understood in the art, and will not be further described in thefollowing paragraphs.

The second electric control unit 180 generates a third electric signal(S3) for controlling the air valve unit 161 of the air parking brakeelectric control valve 160, and a fourth electric signal (S4) forcontrolling the self-lock unit 162 of the air parking brake electriccontrol valve 160. It should be noted that, in the example above, thefirst electric control unit 140 and the second electric control unit 180are independent from each other. However, in another example, theelectric control air brake system 1 may employ a single control unit toexecute the functions of the first electric control unit 140 and thesecond electric control unit 180.

The front axle relay valve 191 is connected among the front axle airbrake electric control valve 121 and the front axle brake cylinders 130.The rear axle relay valve 192 is connected among the rear axle air brakeelectric control valve 121′ and the rear axle brake cylinders 170. Theparking brake relay valve 193 is connected among air barking brakeelectric control valve 160 and the rear axle brake cylinders 170. Two ofthe anti-lock electromagnetic valves 194 are respectively connected tothe front axle brake cylinders 130 and are connected to the front axlerelay valve 191. The other two of the anti-lock electromagnetic valves194 are respectively connected to the rear axle brake cylinders 170 andare connected to the rear axle relay valve 192. The front axle relayvalve 191, the rear axle relay valve 192, the parking brake relay valve193 and the anti-lock electromagnetic valves 194 are well-understood inthe art, and will not be further described in the following paragraphs.In one example, the front axle relay valve 191 may be configured as aquick release valve.

For service brake consideration, when it is desired to decelerate orstop a moving vehicle, the first electric control unit 140 is operatedto generate the first electric signal (S1) and the second electricsignal (S2) for performing the brake function (via the front axle brakecylinders 130 and the rear axle brake cylinders 170).

Specifically, when there is no manual operation, the manual controlpressure regulator 110 would not output compressed air. That is to say,the second pressure (P2) and the third pressure (P3) are substantiallyequal to the ambient air pressure. Thus, the fifth pressure (P5) outputby the front axle air brake electric control valve 121 is the fourthpressure (P4), and the seven pressure (P7) output by the rear axle airbrake electric control valve 121′ is the sixth pressure (P6). The fourthpressure (P4) and the sixth pressure (P6) are respectively control ledby the first electric signal (S1) and the second electric signal (S2),and are irrelevant to manual control. At this time, the intensity of thebrake function is control led by the first electric control unit 140.

When there exists manual operation (for example, via a pedal), themanual control pressure regulator 110 would output compressed air. Thatis to say, the second pressure (P2) and the third pressure (P3) arehigher than the ambient air pressure. Thus, the fifth pressure (P5)outputted by the front axle air brake electric control valve 121 isequal to the greater one of the second pressure (P2) and the fourthpressure (P4), the seven pressure (P7) outputted by the rear axle airbrake electric control valve 121′ is equal to the greater one of thethird pressure (P3) and the sixth pressure (P6). At this time, theintensity of the brake function is not necessarily controlled by thefirst electric control unit 140. When the second pressure (P2) and thethird pressure (P3) resulting from the manual operation are respectivelyhigher than the fourth pressure (P4) and the sixth pressure (P6), theintensity of the brake function is manually controlled. As a result, ifthe moving vehicle needs to be stopped under special consideration(e.g., an emergency), the brake function is controlled by manualoperation. In other words, the manual control has priority over theelectric control.

For parking brake consideration, when it is desired to prevent astationary vehicle from moving, the second electric control unit 180 isoperated to generate the third electric signal (S3) and the fourthelectric signal (S4) for performing the brake function.

Specifically, when there is no manual operation, the air parking brakemanual valve 150 is in the traveling position, and outputs the firstpressure (P1) The air valve unit 161 of the air parking brake electriccontrol valve 160 is able to be controlled by the third electric signal(33) to be switched to the second position to thereby stop outputtingthe first pressure (P1) so as to perform the brake function. Theself-lock unit 162 of the air parking brake electric control valve 160is able to be controlled by the fourth electric signal (S4) to beswitched to the lock position to thereby keep the air valve unit 161 inthe second position. At this time, the brake function and the lockfunction are controlled by the second electric control unit 180.

When there exists a manual operation where the air parking brake manualvalve 150 is manually switched into the parking position, the airparking brake manual valve 150 stops outputting the first pressure (P1),and the air valve unit 161 of the air parking brake electric controlvalve 160 thereby cannot output the first pressure (P1) so that thebrake function is performed. As a result, if a vehicles unable to bekept stationary by the second electric control unit 180, the brakefunction can be achieved by manual operation. In other words, the manualcontrol has priority over the electric control.

In summary, the electric control air brake system 1 is able to executeservice brake and parking brake by electric control, and is able to beintegrated with a digital control software to accomplish assisteddriving technique (e.g., autonomous emergency braking (AEB), electronicbrake system (EBS), adaptive cruise control (ACC) or autonomousdriving).

In addition, to avoid the use of expensive and complex electric controlcomponents, the electric control air brake system 1 according to thedisclosure can be made by retrofitting a conventional air brake systemwith the electric control pressure regulator 120 and the air parkingbrake electric control valve 160. The electric control pressureregulator 120 and the air parking brake electric control valve 160 arethe key points of this disclosure, and are bounded by dot-dash brokenlines in FIG. 4 . The other components other than the bounded portionsare similar to/the same as a conventional air brake system.

The front axle air brake electric control valve 121 and the rear axleair brake electric control valve 121′ of the electric control air brakesystem 1 are structurally identical to each other, and are configured asthe same type of air brake electric control valve 2. Referring to FIGS.5 and 6 , an air brake electric control according to the disclosure mayserve as the front axle air brake electric control valve 121 or the rearaxle air brake electric control valve 121′, and includes a valve body200, a shuttle member 300, a force balance unit 310, an electromagneticurge unit 320 and a plug 330.

The valve body 200 has a first passage 210, a second passage 220 thattransversely intersects the first passage 210, a third passage 230 thattransversely intersects the first passage 210, a fourth passage 240 thattransversely intersects the first passage 210, and a fifth passage 250that transversely intersects the first passage 210. The first passage210 has an end that forms a first inlet 211. The second passage 220 hasan end that communicates with the other end of the first passage 210opposite to the first inlet 211, and an opposite end that forms a venthole 221. The third passage 230 is disposed adjacent to the first inlet211, and has an end that communicates with the first passage 210, and anopposite end that forms an outlet 231. The fourth passage 240 isdisposed adjacent to the second passage 220, and has an end thatcommunicates with the first passage 210, and an opposite end that formsa second inlet 241. The fifth passage 250 has an end that communicateswith the intersection between the first passage 210 and the thirdpassage 230, and an opposite end that serves as a vent hole 251 and thatis blocked by the plug 330. The first passage 210 has an intermediatesection 212 that is located between the third passage 230 and the fourthpassage 240. The valve body 200 further has a first shoulder surface 260that corresponds in position to the intermediate section 212 and thatfaces the first inlet 211.

In an example, the first inlet 211 of the air brake electric controlvalve 2 may serve as the first inlet 122 of the front axle air brakeelectric control valve 121 or the first inlet 122′ of the rear axle airbrake electric control valve 121′. The vent hole 211 of the air brakeelectric control valve 2 may serve as the vent hole 125 of the frontaxle air brake electric control valve 121 or the vent hole 125′ of therear axle air brake electric control valve 121′. The second inlet 241 ofthe air brake electric control valve 2 may serve as the second inlet 123of the front axle air brake electric control valve 121 or the secondinlet 123′ of the rear axle air brake electric control valve 121′. Theoutlet 231 of the air brake electric control valve 2 may serve as theoutlet 124 of the front axle air brake electric control valve 121 or theoutlet 124′ of the rear axle air brake electric control valve 121′.

The shuttle member 300 is disposed at an intersection between the firstpassage 210 and the third passage 230, and has a first blocking surface301 that faces the first inlet 211, and a second blocking surface 302that faces the intermediate section 212. The shuttle member 300 isoperable to move between a first blocking position (see FIG. 6 ) and asecond blocking position (see FIGS. 7 to 10 ). When the pressure in thefirst inlet 211 is higher than the pressure in the intermediate section212, the shuttle member 300 is moved to the first blocking positionwhere the shuttle member 300 is locate at one side of the third passage230 distal from the first inlet 211 and where the shuttle member 300blocks the first passage 210 with the second blocking surface 302thereof such that the first inlet 211 and the outlet 231 are in fluidcommunication and that the intermediate section 212 and the outlet 231are not in fluid communication. When the pressure in the first inlet 211is lower than the pressure in the intermediate section 212, the shuttlemember 300 is moved to the second blocking position where the shuttlemember 300 is locate at another side of the third passage 230 distalfrom the intermediate section 212 and where that shuttle member 300blocks the first passage 210 with the first blocking surface 301 thereofsuch that the first inlet 211 and the outlet 231 are not in fluidcommunication and that the intermediate section 212 and the outlet 231are in fluid communication.

The force balance unit 310 includes an air guide member 311 that extendsfrom the intersection between the first passage 210 and the secondpassage 220 toward the intersection between the first passage 210 andthe fourth passage 240, and an air guide spring 312 that surrounds theair guide member 311. The air guide member 311 has a base portion 313, aneck portion 314 and a head portion 315 that are sequentiallyinterconnected. The base portion 313 is located at the intersectionbetween the first passage 210 and the second passage 220. The neckportion 314 is located at the intersection between the first passage 210and the fourth passage 240. The head portion 315 is located at theintermediate section 212. The air guide member 311 further has an airguide shoulder surface 316 that is located between the neck portion 314and the head portion 315 and that faces the base portion 313. The airguide member 311 further has a through hole 317 that extends in theextending direction of the first passage 210 and that extends throughthe base portion 313, the neck portion 314 and the head portion 315.

The air guide member 311 is operable to move between a first air guideposition (see FIG. 8 ) and a second air guide position (see FIGS. 6, 7,9 and 10 ). When the air guide member 311 is at the first air guideposition, the air guide shoulder surface 316 is spaced apart from thefirst shoulder surface 260 and cooperates with the first shouldersurface 260 to define a first gap (G11) therebetween. When the air guidemember 311 is at the second air guide position, the air guide shouldersurface 316 abuts against the first shoulder surface 260 such that theintermediate section 212 and the fourth passage 240 are not in fluidcommunication. The air guide spring 312 resiliently biases the air guidemember 311 toward the second air guide position.

The electromagnetic urge unit 320 is disposed at the other end of thefirst passage 210 opposite to the first inlet 211. The electromagneticurge unit 320 has a coil 321, a movable column 322 that is driven by thecoil 321, and an electromagnetic spring 323 that abuts against themovable column 322. The movable column 322 is operable to move betweenan urging position (see FIGS. 8 and 9 ) and a retracted position (seeFIGS. 6, 7 and 10 ). The electromagnetic spring 323 resiliently biasesthe movable column 322 toward the retracted position. When the movablecolumn 322 is at the urging position, the movable column 322 is movedagainst the biasing action of the electromagnetic spring 323 to projectout of the coil 321, and pushes the air guide member 311 with an urgeforce such that the through hole 317 of the air guide member 311 isblocked and that the air guide member 311 is moved to the first airguide position against the biasing action of the air guide spring 312.When the movable column 322 is at the retracted position, the movablecolumn 322 is biased by the electromagnetic spring 323 to retract intothe coil 321, and a second gap (G12) is formed between the movablecolumn 322 and the air guide member 311 such that the intermediatesection 212 is in fluid communication with the second passage 220 viathe through hole 317 of the air guide member 311 and the second gap(G12), and that the air guide member 311 is biased to move to the secondair guide position by the air guide spring 312.

When the pressure in the first inlet 211 is higher than the pressure inthe intermediate section 212 (i.e., the second pressure (P2) is higherthan the fourth pressure (P4), or the third pressure (P3) is higher thanthe sixth pressure (P6)), the shuttle member 300 is at the firstblocking position, and the pressure input into the first inlet 221 isdirectly outputted via the outlet 231. At this time, the force balanceunit 310 and the electromagnetic urge unit 320 are irrelevant to theoutputted pressure via the outlet 231. In other words, the brakefunction is manually controlled.

When the pressure in the first inlet 211 is lower than the pressure inthe intermediate section 212 (i.e., the second pressure (P2) is lowerthan the fourth pressure (P4), or the third pressure (P3) is lower thanthe sixth pressure (P6)), the shuttle member 300 is at the secondblocking position, and the pressure output via the outlet 231 is equalto the pressure in the intermediate section 212. At this time, the forcebalance unit 310 and the electromagnetic urge unit 320 control theoutput pressure via the outlet 231. In other words, the brake functionis electrically controlled. Specifically, the air brake electric controlvalve 2 is switched among an initial state, a pressure-increasing state,a pressure-maintaining state and a pressure-release state.

Referring to FIG. 7 , when the air brake electric control valve 2 is inthe initial state, the coil 321 of the electromagnetic urge unit 320 isnot energized, and the movable column 322 is at the retracted position.The air guide member 311 of the force balance unit 310 is at the secondair guide position, so the intermediate section 212 and the fourthpassage 240 are not in fluid communication. The pressure theintermediate section 212 is not affected by the pressure in the secondinlet 241, and cannot be increased, so the brake function is notperformed.

Referring to FIG. 8 , when the air brake electric control valve 2 is inthe pressure-increasing state, the coil 321 of the electromagnetic urgeunit 320 is energized, and the movable column 322 is at the urgingposition. The air guide member 311 of the force balance unit 310 is atthe first air guide position, so the intermediate section 212 and thefourth passage 240 are in fluid communication. The pressure in theintermediate section 212 is affected by the pressure in the second inlet241 to be increased, so the brake function is performed.

Referring to FIG. 9 , the air guide member 311 is pushed by the urgeforce exerted by the movable column 322, and is further subjected to acounter force in a direction opposite to that of the urge forceresulting from the pressure in the intermediate section 212. As such,when the pressure in the intermediate section 212 is increased to reacha predetermined degree, the counter force balances out the urge force sothat the air brake electric control valve 2 is switched into thepressure-maintaining state. In the pressure-maintaining state, the airguide member 311 of the force balance unit 310 is at the second airguide position, so the intermediate section 212 and the fourth passage240 are not in fluid communication, and the pressure in the intermediatesection 212 is thereby stopped from being increased, and is kept at thepredetermined degree in which the counter force resulting from thepressure in the intermediate section 212 is sufficient to balance outthe urge force. When the pressure in the intermediate section 222decreases such that the counter force resulting from the pressure in theintermediate section 212 is insufficient to balance out the urge force,the air guide member 311 of the force balance unit 310 is moved to thefirst air guide position, and the air brake electric control valve 2 isswitched into the pressure-increasing state. Therefore, the pressure inthe intermediate section 212 can be controlled by controlling the urgeforce generated by the electromagnetic urge unit 320. Specifically, whenthe electric current in the coil 321 is greater, the urge forcegenerated by the electromagnetic urge unit 320 is greater, so thepressure in the intermediate section 212 needs to be increased to ahigher degree to generate a sufficient counter force to balance out theurge force so that the air brake electric control valve 2 is switchedinto the pressure-maintaining state. When the electric current in thecoil 321 is smaller, the urge force is smaller, so the pressure in theintermediate section 212 only needs to be increased to a relatively lowdegree to generate a sufficient counter force to balance out the urgeforce for switching the air brake electric control valve 2 into thepressure-maintaining state. Since the electromagnetic urge unit 320 iscontrolled by the first electric signal (S1) and the second electricsignal (S2), the intensity of the brake function is controlled by thefirst electric control unit 140.

Referring to FIG. 10 , to lower the pressure in the intermediate section212, the electric current in the coil 321 needs to be lowered so as tomove the movable column 322 to the retracted position. At this time, theintermediate section 212 is in fluid communication with the secondpassage 220 via the through hole 317 and the second gap (G12), so thepressure in the intermediate section 212 can be released via the outlet221. When the pressure in the intermediate section 212 is lowered to apredetermined degree, the air brake electric control valve is switchedinto the pressure-maintaining state. As such, the intensity of the brakefunction is controlled by controlling the electric current in the coil321. The coil 321 is de-energized when the brake function is notdesired.

In summary, the function of the air brake electric control valve 2 meetsthe requirements of the front axle air brake electric control valve 121and the rear axle air brake electric control valve 121′. The outputpressure of the air brake electric control valve 2 can be controlled bythe first electric control unit 140. In addition, the air brake electriccontrol valve 2 is configured as a force-balance type valve. Differentinput current (in the coil 321) generates different output pressure viathe force balance unit 310. There is no need of a pressure sensor toobtain a feedback value. By merely controlling the current in the coil321, the air brake electric control valve 2 is able to output desiredpressure by virtue or the pressure-increasing, the pressure-maintainingand the pressure-release functions thereof. The air brake electriccontrol valve 2 can be controlled in a simple way, is relativelyinexpensive, and is prevented from the malfunctions commonly associatedwith a pressure sensor. A conventional air brake system can be easilyretrofitted with the air brake electric control valve 2 according to thedisclosure to become an electrically-controlled brake system. In theelectric control air brake system 1 according to the disclosure, two airbrake electric control valves 2 are integrated to serve as the electriccontrol pressure regulator 120 (see FIG. 11 , the two air brake electriccontrol valves 2 respectively correspond to the front axle air brakeelectric control valve 121 and the rear axle air brake electric controlvalve 121′). The front axle brake cylinders 130 and the rear axle brakecylinders 170 can be simultaneously controlled by the electric controlpressure regulator 120. However, a single air brake electric controlvalve 2 is able to solely control the front axle brake cylinders 130 orthe rear axle brake cylinders 170 unassisted. Referring to FIG. 12 , inan example, a single air brake electric control valve 2 whichcorresponds to the front axle air brake electric control valve 121 isconnected to the front axle relay valve 191 to control the front axlebrake cylinders 130. Similarly, a single air brake electric controlvalve 2 which corresponds to the rear axle air-brake electric controlvalve 121′ may be connected to the rear axle relay valve 192 to controlthe rear axle brake cylinders 170.

It should be noted that, when the air brake electric control valve 2malfunctions, the plug 330 can be manually removed for releasing thepressure in the air brake electric control valve 2 via the vent hole251.

Referring to FIGS. 13, 14 and 16 , an air parking brake electric controlvalve 4 according to the disclosure is able to serve as the air parkingbrake electric control valve 160 of the electric control air brakesystem 1. The air parking brake electric control valve 4 includes an airvalve unit 400 and a self-lock unit 500.

The air valve unit 400 includes a main valve body 410, an auxiliaryvalve body 420, a valve core 430 and a first electromagnetic assembly440. The main valve body 410 has a first passage 450, a second passage460 that transversely intersects the first passage 450, a third passage470 that transversely intersects the first passage 450, and a fourthpassage 480 that transversely intersects the first passage 450. Thefirst passage 450 has an open end 451 and a closed end 452. The secondpassage 460 is disposed adjacent to the closed end 452 of the firstpassage 450, and has an end that communicates with the first passage450, and an opposite end that forms an inlet 461. The third passage 470is disposed adjacent to the open end 451 of the first passage 450, andhas an end that communicates with the first passage 450, and an oppositeend that forms a vent hole 471. The fourth passage 480 has an end thatcommunicates with a portion of the first passage 450 between the secondpassage 460 and the third passage 470, and an opposite end that forms anoutlet 481.

In an example, the air valve unit 400 may serve as the air valve unit161 of the electric control air brake system 1, the self-lock unit 500may serve as the self lock unit 162 of the electric control air brakesystem 1, and the inlet 461, the outlet 481 and the vent hole 471 mayrespectively serve as the inlet 163, the outlet 164 and the vent hole165.

The auxiliary valve body 420 is connected to the main valve body 410,and defines a driving space 421 therein that communicates with the openend 451 of the first passage 450.

The valve core 430 is rod-shaped, and has an air guide section 431 thatis disposed in the first passage 450, and a driving section 432 that isdisposed in the driving space 421. The air guide section 431 has a rodbody portion 433, a partition portion 434 that surrounds the rod bodyportion 433, and a blocking portion 435 that surrounds the rod bodyportion 433. The rod body portion 433 is embedded with a rod spring 436.The partition portion 434 divides the first passage 450 into a firstchamber 453 that is proximate to the closed end 452 and thatcommunicates with the second passage 460, and a second chamber 454 thatis distal from the closed end 452 and that communicates with the thirdpassage 470. The partition portion 434 includes two spaced-apart annularribs 437. The annular ribs 437 cooperatively define a buffer chamber 455therebetween that is located between the first chamber 453 and thesecond chamber 454. The blocking portion 435 is disposed at the open end451 and serves to prevent fluid communication between the second chamber454 and the driving space 421. The driving section 432 has an engaginggroove 438 formed in an outer surrounding surface thereof, and a pistonportion 439 at an end thereof opposite to the air guide section 431. Thepiston portion 439 divides the driving space 421 into the third chamber422 that is proximate to the main valve body 410, and a fourth chamber423 that is distal from the main valve body 410.

The first electromagnetic assembly 440 is disposed on an end of theauxiliary valve body 420 opposite to the main valve body 410, andincludes a coil 441, a movable column 442 that is driven by the coil441, and an electromagnetic spring 443 that abuts against the movablecolumn 442. The movable column 442 is operable to move between an intakeposition and a vent position. The electromagnetic spring 443 resilientlybiases the movable column 442 toward the vent position. The valve core430 driven by the first electromagnetic assembly 440 to move between afirst action position and a second action position. The rod spring 436resiliently biases the valve core 430 toward the first action position.

When the valve core 430 is at the first action position (see FIG. 14 ),the partition portion 434 is distal from the closed end 452, and a firstgap (G21) that communicates the first chamber 453 and the fourth passage480 is formed between the partition portion 434 and the main valve body410. When the valve core 430 is at the second action position (see FIG.15 ), the partition portion 434 is proximate to the closed end 452, thefirst gap (G21) is closed, and a second gap (G22) that communicates thesecond chamber 454 and the fourth passage 480 is formed between thepartition portion 434 and the main valve body 410.

When the movable column 442 of the first electromagnetic assembly 440 isat the intake position (see FIG. 18 ), the coil 441 is energized(activated by the third electric signal (S3)), and the movable column442 is retracted relative to the coil 411 against the biasing action ofthe electromagnetic spring 443, is configured not to block an intakepassage 491 that communicates the fourth chamber 423 with the firstchamber 453, and is configured to block a vent passage 492 thatcommunicates the fourth chamber 423 with the outside surrounding, suchthat the fourth chamber 423 expands to move the valve core 430 to thesecond action position against the biasing action of the rod spring 436.When the movable column 442 of the first electromagnetic assembly 440 isat the vent position (see FIGS. 16, 17 and 19 ), the coil 441 isde-energized, and the movable column 442 is biased by theelectromagnetic spring 443 to project relative to the coil 441, isconfigured to block the intake passage 491, and is configured to notblock a vent passage 492, such that the rod spring 436 biases the valvecore 430 back to the first action position and that the fourth chamber423 shrinks. FIG. 20 illustrates an example of the configuration of theintake passage 491 and the vent passage 492. However, one skilled in theart is able to design an equivalent passage structure, and theconfiguration of the intake passage 491 and the vent passage 492 is notlimited to the example in FIG. 20 . It should be noted that the intakepassage 491 may communicate with an inner space of the rod body portion433 to aid the biasing action of the rod spring 436.

The self-lock unit 500 is disposed on the auxiliary valve body 420, andincludes a second electromagnetic assembly 510 and a proof assembly 520.The second electromagnetic assembly 510 includes a coil 511, a movablecolumn 512 that is driven by the coil 511, and a self-lock spring 513that abuts against the movable column 512. The movable column 512 of thesecond electromagnetic assembly 510 is operable to move between arelease position and a lock position. When the movable column 512 of thesecond electromagnetic assembly 510 is at the release position (seeFIGS. 16, 17 and 18), the movable column 512 is retracted relative tothe coil 511 against the biasing action of the self lock spring 513, andis configured not to engage the engaging groove 438 of the valve core430, so that the valve core 430 is movable between the first actionposition and the second action position. When the movable column 512 ofthe second electromagnetic assembly 510 is at the lock position (seeFIG. 19 ), the movable column 512 is biased by the self-lock spring 513to project relative to the coil 511 and to engage the engaging groove438 of the valve core 430, so that the valve core 430 is kept at thesecond action position.

The proof assembly 520 includes an outer casing 521 that covers thesecond electromagnetic assembly 510, a bolt member 522 that is movablymounted to the outer casing 521, and a cord 523 that is connectedbetween the bolt member 522 and the movable column 512 of the secondelectromagnetic assembly 510. Under normal circumstances, the cord 523is loose, and would not affect the operation of the movable column 512of the second electromagnetic assembly 510. When the air parking brakeelectric control valve 4 malfunctions during parking brake, the boltmember 522 can be manually separated from the outer casing 521 to pullthe movable column 512 of the second electromagnetic assembly 510 viaole cord 523 for separating the movable column 512 from the valve core430 so as to release the parking brake. The parking brake can beperformed via operating the air parking brake manual valve 150.

Specifically, the air parking brake electric control valve 4 isswitchable among a release state, a first phase state, a second phasestate and a rock state. When a vehicle is traveling, the air parkingbrake electric control valve 4 should be in the release state. When avehicle is parking, the air parking brake electric control valve 4should be in the lock state. The first phase state and the second phasestate are transition states during the switch between the release stateand the lock state.

Referring to FIG. 16 , when in the release state, the coil 441 of thefirst electromagnetic assembly 440 and the coil 511 of the secondelectromagnetic assembly 510 are not energized, the movable column 442of the first electromagnetic assembly 440 is at the vent position, thevalve core 430 is at the first action position, and the movable column512 of the second electromagnetic assembly 510 is not aligned with theengaging groove 438 of the valve core 430 and is unable to engage theengaging groove 438 (substantially release position). The air enteringvia the inlet 461 sequentially flows through the second passage 460, thefirst chamber 453, the first gap (G21) and the fourth passage 480 toexit via the outlet 401 (see FIG. 14 ). As such, when there is no manualoperation and when the air parking brake electric control valve 4 is atthe release state, the rear axle brake cylinders 170 would not performthe brake function, and the vehicle travels freely.

During the switch from the release state to the lock state, the airparking brake electric control valve 4 is sequentially switched into thefirst phase state and then the second phase state.

Referring to FIG. 17 , when in the first phase state, the coil 441 ofthe first electromagnetic assembly 440 is not energized, and the coil511 of the second electromagnetic assembly 510 is energized. The movablecolumn 442 of the first electromagnetic assembly 440 is at the ventposition, the valve core 430 is at the first action position, and themovable column 512 of the second electromagnetic assembly 510 is at therelease position. Since the coil 511 of the second electromagneticassembly 510 is energized, the movable column 512 of the secondelectromagnetic assembly 510 is retracted relative to the coil 511 ofthe second electromagnetic assembly 510 against the biasing action ofthe self-lock spring 513. As such, there is no friction generatedbetween the valve core 430 and the movable column 512 of the secondelectromagnetic assembly 510, and the movable column 512 of the secondelectromagnetic assembly 510 would not engage the engaging groove 430 ofthe valve core 430. When there is no manual operation and when the airparking brake electric control valve 4 is in the first phase state, therear axle brake cylinders 170 would not perform the brake function, andthe vehicle travels freely.

Referring to FIG. 18 , when in the second phase state, the coil 441 ofthe first electromagnetic assembly 440 and the coil 511 of the secondelectromagnetic assembly 510 are energized. The movable column 442 ofthe first electromagnetic assembly 440 is at the intake position, thevalve core 430 is at the second action position, and the movable column512 of the second electromagnetic assembly 510 is at the releaseposition. Since the coil 511 of the second electromagnetic assembly 510is energized, the movable column 512 of the second electromagneticassembly 510 is retracted relative to the coil 511 of the secondelectromagnetic assembly 510 against the biasing action of the self-lockspring 513, and is configured to not engage the engaging. Groove 438 ofthe valve core 430. Since the valve core 430 is at the second actionposition, the air entering via the inlet 461 is prevented from flowingto the outlet 481, and the air at the outlet 481 is able to flow via thefourth passage 480, the second gap (G22), the second chamber 454, andthe third passage 470 to the vent hole 471 (see FIG. 15 ). As such,regardless of whether or not there is manual operation, when the airparking brake electric control valve 4 is at the second phase state, therear axle brake cylinders 170 would perform the brake function, and thevehicle is control led electrically to be kept stationary. It should benoted that the coil 441 of the first electromagnetic assembly 440 andthe coil 511 of the second electromagnetic assembly 510 may consumeconsiderable energy and generate considerable heat when the air parkingbrake electric control valve 4 is kept in the second phase state for along period of time, so the air parking brake electric control valve 4should be switched to the lock state for saving energy and forpreventing the coil 441 of the first electromagnetic assembly 440 andthe coil 511 of the second electromagnetic assembly 510 to burn out.

Referring to FIG. 19 , when in the lock state, the coil 441 of the firstelectromagnetic assembly 440 and the coil 511 of the secondelectromagnetic assembly 510 are not energized. The movable column 442of the first electromagnetic assembly 440 is at the vent position, thevalve core 430 is at the second action position, and the movable column512 of the second electromagnetic assembly 510 is biased by theself-lock spring 513 to engage the engaging groove 438 of the valve core430. Since the valve core 430 is at the second action position, the airentering via the inlet 461 is prevented from flowing to the outlet 481,and the air at the outlet 481 is able to flow via the fourth passage480, the second gap (G22), the second chamber 454, and the third passage470 to the vent hole 471 (see FIG. 15 ). As such, regardless of whetheror not there is manual operation, when the air parking brake electriccontrol valve 4 is at the lock state, the rear axle brake cylinders 170would perform the brake function, and the vehicle is controlledelectrically to be kept stationary. It should be noted that the coil 441of the first electromagnetic assembly 440 and the coil 511 of the secondelectromagnetic assembly 510 may not consume energy and may not burn outwhen the air parking brake electric control valve 4 is in the lockstate.

During the switch from the lock state to the release state, the airparking brake electric control valve 4 is sequentially switched into thesecond phase state and then the first phase state.

Referring to FIG. 18 , when in the second phase state, the movablecolumn 442 of the first electromagnetic assembly 440 is at the intakeposition, the valve core 430 is at the second action position, and themovable column 512 of the second electromagnetic assembly 510 is at therelease position. At this time, since the fourth chamber 423 is filledwith compressed air, the movable column 512 of the secondelectromagnetic assembly 510 can be easily separated from the engaginggroove 438 of the valve core 430. If the coil 511 of the secondelectromagnetic assembly 510 is directly energized without switching theair parking brake electric control valve 4 into the second phase state(i.e., without energizing the coil 441 of the first electromagneticassembly 440), the movable column 512 of the second electromagneticassembly 510 may not be easily separated from the engaging groove 438 ofthe valve core 430.

Referring to FIGS. 16 and 17 , after the movable column 512 of thesecond electromagnetic assembly 510 is separated from the engaginggroove 438 of the valve core 430, the coil 441 of the firstelectromagnetic assembly 440 is first de-energized so that the airparking brake electric control valve 4 is temporarily switched into thefirst phase state, and the coil 511 of the second electromagneticassembly 510 is then de-energized so that the air parking brake electriccontrol valve 4 is switched into the release state. It should be notedthat the coil 441 of the first electromagnetic assembly 440 and the coil511 of the second electromagnetic assembly 510 may not consume energyand may not burn out when the air parking brake electric control valve 4is in the release state since the coil 441 of the first electromagneticassembly 440 and the coil 511 of the second electromagnetic assembly 510are not energized.

The air parking brake electric control valve 4 is operable to switchbetween the release state and the lock state by the second electriccontrol unit 180. When the vehicle is parking, if the parking brakefunction is not manually activated, the second electric control unit 180would electrically activate the parking brake function. A conventionalair brake system can be easily retrofitted with the air parking brakeelectric control valve 4 so as to become an electrically-controlled airbrake system. In an example, the air parking brake electric controlvalve 4 is an assembly of commercial normally-open three-porttwo-position valves and the self-lock unit 500, which is reliable andinexpensive.

In summary, the air brake electric control valve 2 and the air parkingbrake electric control valve 4 according to the disclosure are able toelectrically control the electric control air brake system 1. Inaddition, since the air brake electric control valve 2 and the airparking brake electric control valve 4 work without a pressure sensor,the air brake electric control valve 2 and the air parking brakeelectric control valve 4 according to the disclosure are relativelyinexpensive, and are prevented from the malfunctions commonly associatedwith a pressure sensor. A conventional air brake system can be easilyretrofitted with the air brake electric control valve 2 and/or the airparking brake electric control valve 4 so as to become anelectrically-controlled air brake system.

In the description above, for the purposes of explanation, numerousspecific details have been set forth in order to provide a thoroughunderstanding of the embodiment. It will be apparent, however, to oneskilled in the art, that one or more other embodiments may be practicedwithout some of these specific details. It should also be appreciatedthat reference throughout this specification to “one embodiment,” “anembodiment,” an embodiment with an indication of an ordinal number andso forth means that a particular feature, structure, or characteristicmay be included in the practice of the disclosure. It should be furtherappreciated that in the description, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure and aiding in theunderstanding of various inventive aspects, and that one or morefeatures or specific details from one embodiment may be practicedtogether with one or more features or specific details from anotherembodiment, where appropriate, in the practice of the disclosure.

While the disclosure has been described in connection with what isconsidered the exemplary embodiment, it is understood that thisdisclosure is not limited to the disclosed embodiment but is intended tocover various arrangements included within the spirit and scope of thebroadest interpretation so as to encompass all such modifications andequivalent arrangements.

What is claimed is:
 1. An air brake electric control valve comprising: avalve body having a first passage, a second passage that transverselyintersects said first passage, a third passage that transverselyintersects said first passage, and a fourth passage that transverselyintersects said first passage, said first passage having an end thatforms a first inlet, said second passage having an end that communicateswith another end of said first passage opposite to said first inlet, andan opposite end that forms a vent hole, said third passage beingdisposed adjacent to said first inlet, and having an end thatcommunicates with said passage, and an opposite end that forms anoutlet, said fourth passage being disposed adjacent to said secondpassage, and having an end that communicates with said first passage,and an opposite end that forms a second inlet, said first passagefurther having an intermediate section that is located between saidthird passage and said fourth passage; a shuttle member disposed at anintersection between said first passage and said third passage; a forcebalance unit including an air guide member that extends from theintersection between said first passage and said second passage towardthe intersection between said first passage and said fourth passage, andan air guide spring that surrounds said air guide member, said air guidemember further having a through hole that extends in the extendingdirection of said first passage, said air guide member being operable tomove between a first air guide position and a second air guide position;said air guide spring resiliently biasing said air guide member towardthe second air guide position; and an electromagnetic urge unit disposedat the another end of said first passage opposite to said first inlet,said electromagnetic urge unit having a coil, a movable column that isdriven by said coil, and an electromagnetic spring that abuts againstsaid movable column, said movable column being operable to move betweenan urging position and a retracted position, said electromagnetic springresiliently biasing said movable column toward the retracted position;wherein, when said movable column is at the urging position, saidmovable column is moved against the biasing action of saidelectromagnetic spring to project out of said coil, and pushes said airguide member with an urge force such that said through hole of said airguide member is blocked and that said air guide member is moved to thefirst air guide position against the biasing action of said air guidespring; and wherein, when said movable column is at the retractedposition, said movable column is biased by said electromagnetic springto retract into said coil, and a gap is formed between said movablecolumn and said air guide member such that said intermediate section isin fluid communication with said second passage via said through hole ofsaid air guide member and said gap and that said air guide member isbiased to move to the second air guide position by said air guidespring.
 2. The air brake electric control valve as claimed in claim 1,further comprising a plug, said valve body further having a fifthpassage that transversely intersects said first passage, said fifthpassage having an end that communicates with the intersection betweensaid first passage and said third passage, and an opposite end thatserves as a vent hole and that is blocked by said plug.